physics final
four forces act concurrently on a point as shown. the resultant of the four forces is
0
a certain rubber band stretches 48 cm when an 8 n force is applied. if the rubber band obeys hooke's law, how much force does it take to stretch the rubber band at 6 cm
1.0 n
the conversion factor for changing one unit of length to another in the metric system is a multiple of
10
an athlete runs 40 m north and 30 m south. the resultant displacement of the runner is
10 m north
the approx. number of days in one third of a year is 122. the number of secs in 1/3 of year is
10,540,800
Consider the motion of on obj acted on by a net force. describe a situation that involves net force, acceleration and speed
Net force is positive and so is acceleration and speed
what is the velocity of a car that moves from an initial position of 1200 km to a final position of 200 km in 5 hrs
-200 km/hr
where do you end up relative to your stating point if you walk 30 km north and then 55 km south
-25 km or 25 km south of your starting point
how much force does it require to slow a car down from 70 mph to 20 mph in 5 seconds? the mass of the car is 2500 kg.
-25,000 n
how much force does it take to slow a car from 37 m/s to 12 m/s in 5 seconds? car is 1,400 kg
-7,000 N
a measurement is
a qty and a unit
the expression "per" as in miles per hour or meters per second mathematically indicates
division
the prefix nano means
extremely small
the same engine is place in a large truck and a small car. the engine produces the same amt of force between the vehicle and the road in both cases. the car
has a greater acceleration tan the truck because the car has a smaller mass
the law that states the force applied to a spring is directly proportional to the deformation of the spring is called
hooke's law
if someone asked you "with how much force does gravity pull on you" they are technically asking
how much do you weigh
if gold were sold by weight, would you rather buy it in denver or death valley? if gold were sold by mass, would you rather buy it in denver or death valley? why?? (g is a lower value in the higher elevation)
if gold was sold by weight i'd rather buy it in denver bc the more gravity acts on you the more you weigh and gravity is lower in denver bc of its higher elevation. if gold was sold according to mass, it wouldn't matter where i bought it bc mass is a fundamental property so doesn't change with different locations
the inertia of on object comes from its
mass
three basic qts that are the foundation of physics include
mass time length
what are the characteristics of an object in equilibrium
net force acting on an object is 0, forces are balanced, obj at rest or moving at constant speed
one car travels 65 mph east and another travels 65 mph west. what can you say about the cars speed and velocities
same speed and different velocities
the unit of time most often used by physicists is the
second
if a student aims a dart three times at a bullseye, but hits the locations of 10, 2, 4 on a clock face, you could say
she was neither accurate or precise
if every force has an equal and opposite reaction, why don't all forces cancel out with each other
the action and reaction forces act on different objects
what is not true about action-reaction pair of forces
the action force is applied first and the reaction force appears later at time t
the term at in the equation v = v0 + at represents
the amount the object's velocity has changed
when the punter kicks the football, his foot feels the ball because
the ball exerts a force on his foot as a reaction to the force of his foot on the ball
john is on a skateboard and throws a ball. the skateboard moves in the opposite direction from the thrown ball because
the ball exerts a reaction force on him as it is being thrown
the elapsed time a projectile spends in the air is the
time of flight
what is the speed equation
v=d/t
the slope of a distance versus time graph represents
velocity
what is the slope of a d/t graph
velocity
the equation v = v0 + at relates which three variables
velocity, acceleration and time
two projectiles are launched at different angles. one is launched at 30 degrees and the other at 60 degrees. what can you say about the vertical and horizontal components
vertical component for 60 is higher but horizontal component for both angles are the same
a spring stretches 18 cm when a force of 5 n is applied. the spring constant is
.278 n/cm
a ball is rolled across the lvl surface of a desk at a speed of 3 m/s. a target is placed .75 m from the desk. what is the height of the desk?
.306 m
the distance between the pitcher's mound and home plate is 60 ft and 6 inches. the astros starting pitcher throws an average fast ball of 90 mph. how long does it take for ball to get to home plate?
.458 seconds
a ball is thrown vertically upwards with an initial speed of 5 m/s. what is the time for the ball to reach its max height? how long is the ball in the air
.5, 1.02 ttl time in air
a block w a mass of 1 kg sits on a smooth, dry level surface. the coefficient of dry sliding friction is .1. a force of 1.5 n is applied to the block. the block will start accelerating at what rate
.5m/s^2
A wagon with mass of 25 kg has a force of 50 n to the right and forces of 25 n and 10 n to the left. The acceleration of the wagon is
.6 m/s^2 to the right
a force of 25 n is required to slide a physics txt bk at constant speed over the dry surface of a table. the txt bk has a mass of 3 kg. the coefficient of sliding friction is
.85
the engine of a rocket accelerates fuel backward to push rocket forward. the mass of the rocket is 17,000 kg. the rocket accelerates 14 kg of fuel backward at 1,200 m/s^2. the forward acceleration of the rocket is
.99 m/s^2
the slope of a distance versus time graph for a bicycle rider is 0 for a 75 minute time interval. what is the bicycle rider's speed during this time interval?
0
a 2,000 kg car is traveling due north at a constant speed of 30 m/sec. what is the net force acting on the car and why
0 N because it is in equilibrium due to constant speed
the coefficient of friction is usually a number between
0 and 1
what is the displacement of the tennis ball if it went back and forth on a 23.77 m court>
0 m
an object is thrown straight upwards with a speed of 78.4 m/s eight seconds laters its speed
0 m/sec
a penny has which mass (60,000 g 2,000 kg 6x10^24 kg 1.0 g)
1 g
organize the following from largest to smallest: 15 mm, 50 cm, 10 m, 1 km
1 km, 10 m, 50 cm, 15 mm
sud could jump 1.25 m off of the floor. what was his hang time/ttl amt of time he was in the air?
1.02 s
10,765,000,000 in scientific notation
1.0765 x 10^10
a 10 n force directed south and a 10 n force directed west both act on the same point. the resultant of these two forces is
10 root 2 n
the kilogram, the unit used as the standard for mass, is equal to the mass of
1000 cubic centimeters of water
if you have a mass of 50 kg and want to jump in the air you could push down on the floor with 1000 n and the floor would push back up
1000 n
a machine for lifting heavy equipment uses a steel cable. the equipment is support by 6 strands of cable. the equipment being lifted has a mass of 7200 kg. what is teh force in each of the six supporting cables?
11,760 n
a force of 180 lbs is applied to a wagon that weighs 155 lbs. the acceleration of the wagon is closest to
11.36 m/s^2
an object is observed to have an acceleration of 9 m/s^2 when a net force of 108 newtons is applied. the mass of the object is
12 kg
three forces are acting on an obj. obj is not moving. two forces include a 9 n force to the right and a 21 n force to the left. third force is
12 n to the right
an object falls for 13 seconds after being dropped from rest. its speed is approximately
127.4 m/s
a horse won a 1 mile (1.6 km) race with a time of 2 minutes and 2.66 seconds. calculate horse's average speed in m/s
13.04
a rock with a weight of 1372 n on earth has a weight of 1970 n on neptune. what is the value of the acceleration of gravity (g) on neptune
14.07 m/s^2
an object is launched at an angle of 45 degrees with a speed of 20 m/s. calculate the initial velocity components (x and y), the time it takes to get to its max height, the time it takes to hit the ground, the range, and the max height it reaches
14.14 m/s = x and 14.14 m/s = y, time it takes to hit ground = 2.88 s, the range = 10.2 m, max height it reaches = 40.72 m
student calculate depth of a hole to be 75 meters. how long did it take for rock to reach bottom
15.31
a 20 n force is pushing 2 blocks horizontally along a friction less floor. what is the force the 8 kg mass exerts on the 2 kg mass?
16 n
a 2 kg ball is observed to accelerate at 8000 m/s^2 as it is hit with a bat. how much force is exerted on the bat by the ball?
16,000 n
what is the depth of a hole that takes a rock 6 secs to hit bottom
176.4 m
the weight of a 2 kg mass is equal to __ newtons and __ pounds
19.57/4.4
how fast must an object be thrown upward if it is to stay in the air for 4 seconds before hitting the ground again
19.6 m/s
a truck has which mass (60,000 g 2,000 kg 6x10^24 kg 1.0 g)
2,000 kg
a box is sliding along a dry, level surface with a coefficient of sliding friction of .25. if the force of friction is 5 newtons, what is the mass of the box
2.04 kg
a force of 5 newtons acts on an obj w a mass of 2 kg what is the acceleration
2.5 n/kg
how many centimeters in an inch
2.54 cm
the height of an average professional basketball player is about 2 meters, convert to centimeters and millimeters
200 cm and 2000 mm
what is the final position of a mosquito that flies from an initial position of 30 cm in 3o seconds at -.30 m/s
21.0 m
a golfer hits a golf ball at a 35 degree angle at a speed of 37 m/s. the y component to which the ball travels is
21.22 n
a rocket has an acceleration of 50 m/s^2. how long does it take the rocket to reach a speed of 1,200 m/sec
24.0 sec
an arrow is shot straight up into the air at a speed of 68.6 m/s. what is the maximum height reached by the arrow? you may neglect air friction.
240.1 m
bill pushes his mower across a lvl lawn at a constant speed by applying a force of 50 n to the handle at an angle of 60 degrees to the ground. calc the component of the 50 n force responsible for moving the mower
25 n
if an electronic timer shows the display 6:58:58.19, the time in seconds is
25,138.19
the conversion factor for changing one unit of length to another in the English system may be (3)
3 12 5280
if you ride the gravitron amusement ride, you will accelerate at 29.4 m/s^2. express the acceleration in the number of g's you would experience riding it
3 g's
at an altitude of 400 km, the circumference of the shuttle's orbit is 36 million meters. how long does it take for the shuttle to go around the earth one time at the speed of 11,000 m/s
3,272.7 seconds
the light rail train slows down with an average deceleration of -1.8 m/s^2. how long does it take the train to slow down for 6.0 m/s to a complete stop?
3.33 seconds
potatoes weigh 8.0 lbs at HEB. the ttl mass of potatoes is
3.64 kg
a 4 kg mass is suspended from a spring that has a spring constant of 10 n/cm. the spring stretches by
3.91 cm
a water balloon is launched horizontally at a height of 1.5 m above the ground. its launch speed is 30 m/s. the instant before the balloon hits the ground, its horizontal speed is
30 m/s
the wires inside computer chips are about the smallest structures produced by human technology and are (size in comparison to a hair)
300 times smaller than a hair
a spherical storage tank has a diameter of 10 meters (a) if you had the job to paint SA, how much paint would you need to purchase in m^2 (b) how much volume can the tank hold in m^3
314 m^2 galloons of paint//523 m^3 of stuff
what was average lap time from question before?
35.00 secs
the distance traveled by the telsa is
350 meters
if a space shuttle is traveling at a speed of 11,000 meters per second, how far does it travel in km per hour
39,600 km
a race car driver won a 500 mile race with an average speed of 144 mph. the track is an oval 1.4 miles long. how long did it take him to complete the race in hours: minutes: seconds
3:28:20
Elizabeth walked in a straight line from a starting position of 800 meters to a finish position of 500 meters at a constant velocity of -1.25 m/s. how long did it take her?
4 minutes
a 10 kg mass is suspended from a spring that has a spring constant of 20 n/cm. the spring stretches by about
4.9 cm
i run for one hour at 8 mph. then i walk for 30 minutes at 4 mph. i rest for 15 min and then walk home at 3 mph. what is my avg speed in mph?
4.90
an arrow is shot straight up at an initial speed of 30 m/sec how high does the arrow go at its highest point
45.9 m
a tennis court is 23.77 m from baseline to baseline. in a volley, how far does the ball travel?
47.54 m
ab obj falls for 5 seconds after being dropped from rest. speed?
49 m/s down
a refrigerator measures 2 m x 400 mm x 70 cm (a) calculate SA in cm^2 and in m^2 (b) calculate volume in cm^3 and mm^3
49,600 cm^2, 4.96 m// 560,000 cm^3 5.6x10^8 mm^3
a 5 n force directed north and 5 newton force directed west both act on the same point. what is the resultant of these two forces
5 root 2 n
a rocket has an acceleration of 60 m/s^2 how long does it take the rocket to reach a speed of 3000 m/sec
50 secs
convert age to secs (18)
567,648,000 s
the earth has which mass (60,000 g 2,000 kg 6x10^24 kg 1.0 g)
6 x 10^24
Columbus sailed for 71 days at 1.11 m/s, how much distance did he cover in the total trip?
6,809 km
a person has which mass (60,000 g 2,000 kg 6x10^24 kg 1.0 g)
60,000 g
a flock of Canadian geese are flying at 41 mph headed due south. if a 52 mph east wing were to begin blowing, the resultant velocity of the flock would be
66.22 mph
the acceleration of gravity on Jupiter is about 23 m/s^2. a 5 kg object on the planet is dropped from rest. after 3 seconds, the speed of the object is
69.0 m/s
a telsa reaches a speed of 70 m/s in 10 s. the acceleration of the car is
7 m per second per second
an acrobat jumped through a hoop with its lowest point at 246 cm. to achieve this height, what was his initial velocity?
7 m/s
a 2.25 kg ball is observed to accelerate at 3,500 m/s^2 as it is hit with a bat how much force is exerted on the bat by the ball?
7,875 n
which angle gives the same range of a projectile as a 15 degree angle
75 degree
using standard notation, express 29,800 seconds in units as hours:minutes:seconds
8 hrs:16 min:40 secs
a weather balloon is 15 km above the surface of earth. as you watch it, the balloon floats 8 km east and 3 km south of its starting point. what is the balloon's location as a position vector in the form of (x,y,z)
8,15,-3
a bridge can handle 18 people with an average mass of 70 kg per person; the bridge weighs 5000N how strong must the two bridge supports be
8665 n each
if david's point of release was 30 feet from goliath's head and it took 1 sec for the stone to travel, how fast was the stone in moving meters/seconds
9.14
a force of 10 pounds acts on a cart with a weight of 10 lbs. what is the acceleration of the cart?
9.79 m/s^2
the acceleration of a gravity near the earth's surface is
9.8 m/s^2
the weight of a 9.8 kg mass on earth is
96.04 newtons
the weight of a 45 kg bulldog in pounds is
99
The Newton is a unit of force that is defined by
An acceleration of 1 m/s^2 of an obj with a mass of 1 kg
the first US metric study was issued in a report by
John Quincy Adams
if the speed is constant, which variable is zero in the equation x = x0 + v0t + 1/2at^2
a
write newton's second law
a = f/m
what is true about acceleration for a ball thrown vertically upward
a constant acceleration throughout its flight
the rate of change of velocity over time is called
acceleration
what is the slope of a v/t graph
acceleration
newton's second law states
acceleration is directly proportional to net force and inversely proportional to mass
write newton's first law
an object at rest stays at rest an obj in motion stays in motion unless acted upon by an external force
force is best defined as
any action that could change the motion of an object
sir isaac newton is credited with inventing
calculus
sir isaac newton was a student and professor at
cambridge
if there is a weak relationship between two variables, the slope for a graph of the relationship is
close to zero
when constructing a graph, it is NOT a good idea to
connect data points
uniform acceleration is the same thing as
constant acceleration
if no forces are acting on an obj its motion will
continue in the same direction with the same speed
the term that describes the amount of change in a certain direction in the location of an object is
displacement
the area under a speed versus time graph is
distance
the ttl length of a journey from start to finish with no regard to direction is called
distance
tom and frank shoot water balloons using a new launcher tom got for his birthday. package claims it will launch balloons up to 200 yds. the boys launch balloons at various angles to determine the angle that makes the balloons travel the greatest distance. if they were to graph their results, how would the values be placed on the graph?
distance on the y axis, angle on the x axis
if the net force on an obj is zero, it is in --
equilibrium
write newton's third law
for every action there is an equal and opposite reaction
according to newton's first law what must be applied to turn or stop something in motion
force
what action must be taken to change the motion of an obj
force must be applied to obj
force that opposes the motion of an object is called
friction force
which force always opposes the motion of an obj
friction force
the force called weight comes from
gravity
what force is always directed toward the earth's center of mass
gravity
compared to a bicycle, an automobile in neutral pushed by a student has more
inertia
the more mass an object has, the harder it is to start moving or to stop from moving. the tendency of an object to resist changes in motion is called
inertia
what does a negative exponent indicate when scientific notation is used?
it indicates that the value of a the number represented is less than one
a ball with a mass of 55 kg is moving at the same speed as a ball with a mass of 35 kg. compare the force required to stop each of the two balls
it takes more force to stop the 55 kg ball bc the 55 kg ball has more inertia
the units of force come from newton's second law. in the metric system, the units for force are
kg times m^2/sec
3 units to express distance in the metric system
kilometer, nanometer, and centimeter
using the concepts of lubrication, rolling friction and sliding friction, explain what happens when a driver slams on the brakes of a car on a wet road
lubricants are used to reduce friction between 2 surfaces. rolling friction is created by one obj rolling on another. sliding friction is friction created by an obj sliding on the other. by slamming brakes on a wet road, sliding friction changes to rolling fraction since the wetness of the road acts as a lubricant that reduces friction between two surfaces.
give 3 units of speed
m/s ips fps
inertia is directly proportional to --
mass
what is the role of mass in newton's second law
mass is a measure of an object's resistance to acceleration
as you walk with one big giant stride, it would most closely approximate a
meter
the metric unit closest to the thickness of a toothpick is the
millimeter
which system is inherently more accurate: the English or the metric?
neither is more accurate
an obj that is at rest will remain at rest or an obj that is moving will continue to move in a straight line with constant speed, if and only if the net force acting on the obj is zero. this statement is called
newton's first law of motion
karateists can break a concrete block 3.8 cm thick by moving their hand at 11 m/s to create 3069 N. it is hard to believe that something as soft as a hand can break concrete but the bones in the human hand can withstand up to 40 times that amount of force. this is an example of which of newton's laws?
newton's second law of motion
is mass a force
no
is weight constant throughout the universe
no
in physics, free fall means
no forces act on the object except gravity
force that is perpendicular to an object is called
normal force
which force always perpendicular to a surface that acts on an obj
normal force
a moving car that has zero acceleration is
on cruise control
the term that refers to the location of an object is
position
the smallest measurable length of a centimeter stick is 0.001 cm. which of the following best describes this limit?
precision
distance may be expressed as a
product of time and speed
an ice skater feels very little force as she moves in a straight line on her skates. according to newton's first law, what is true of the ice skater's motion
she must apply force with her skates to turn or to stop
acceleration is the __ of the __ versus time graph
slope, velocity
a measure of how quickly an object from one place to another is
speed
velocity is what
speed and direction
a block with a mass of 6.5 kg sits on a smooth, dry, level surface. the coefficient of dry sliding friction is .35. a force of 30 N is applied to the block. the block will
start sliding and accelerate at 1.19 m/s^2
an obj is dropped from the top of a cliff, you are given height of the cliff. the equation to solve for the time it takes for the obj to hit the ground is
t = (2y/g)^1/2
compared to a 2.0 kg chunk of steel, a 2.0 kg bag of popcorn
takes up more space bc its less dense
the maximum speed reached by an object in a free fall where the forces of gravity and air resistance are equal is called
terminal speed
the rolling and static coefficients of friction for a monorail's wheel and the one-bar track on which it runs are .27 and .67. which value is which coefficient and why
the .67 would be the coefficient of static friction and the .27 would be the coefficient of rolling friction since it would take less force to keep the monorail car moving once it starts moving
a ball is tossed vertically; what does this version of the free fall motion equation tell you about the ball's flight? 0 = 1 + 10t - 4.9t^2
the ball's final position is at y = 0 or on the ground, the ball was launched at 1 meter above the ground, the ball was launched upwards with a speed of +10 m/s
in the equation x = x0 + v0t + 1/2 at^2, the term v0t represents
the distance the object would have moved if the speed stayed constant at v0
a vb player w/ a mass of 65 kg jumps upward by pushing against the floor with her ft w/ a force of 1,400 N. which is the best explanation for why the vb's player moves upward
the floor pushes back upward on the player w/ a force of 14,000 newtons which lifts players off of the ground
a force of 1 n is the only force exerted on a block, and the acceleration of the block is measured. when the same force is the only force is the only force exerted on a second block, the acceleration is four times as large. what can you conclude about the masses of the two blcoks
the mass of the second block is one-fourth times the mass of the first block
why is it impossible to have a true vertical line on a distance versus time graph
the object would have moved a distance in zero time
in the equation x = x0 + v0t + 1/2at^2 the variable x0 represents
the position at t = 0
if you traveled to mars where gravity is less than on earth, your mass would be
the same
two objects have the same inertia if
the same forces causes the same acceleration in both objects
two student drivers were moving slowly up a snowy hall. the student in the second car tried to accelerate in order to pass the first car. instead of passing, the second student slid slowly down the hill. explain why this might of happened
the second student may have slid down the hill because by her beginning to accelerate, the snow acted like a lubricant and reduced the friction that was helping her go up the mountain. therefore when part of that friction was removed the driver slid down.
if the dependent values on a graph increase rapidly while the values of the independent variable increase slightly
the slope of the graph is large
what can never happen because it violates newton's first law
the speed of an obj changes even though no forces are acting on the object
soft materials like rubber can have a very high coefficient of friction because
they conform to surfaces and create many points of contact
ball bearings decrease friction because
they replace sliding motion with rolling motion
if you are pulling a wagon on wheels with your little sister to the right, in which direction is the force of friction and what type of friction is involved
to the left and rolling friction
why does the scientific community use the metric system almost exclusively
uses the metric system almost exclusively because conversion factors are multiples of 10 so easier conversions and gives community "common language" so less miscommunication
the force that resists the movement of objects in fluids is called
viscous friction
what is not a way to reduce friction
wear cleated shoes
the force of the earth's gravity pulling down on a person is called
weight
Isabella weighs 150 lbs. ben weighs 90 kg. Olivia weighs 800 N. William weighs 128,000 grams. who weighs the most?
william
a young American girl who is 3.5 ft went on vacation with her family to the Disney park in france. in order to be allowed to get on the ride, the sign says a person must be at least 100 cm. is she tall enough?
yes because she is 106.88 cm tall
in an elevator accelerating upwards at 4.9 m/s^2 how much would you weigh
you would weigh 1.5 more